We are visited in our garden in Churchill, Victoria, Australia by two species of Praying Mantis.
The first is the Purple-winged Mantid – Tenodera australasiae, a long slender animal, mainly brown, but with green showing along its wing edges. We don’t see very many of these, perhaps two in the 20 years we have lived here.
The second is the much smaller Garden Mantid – Orthodera ministralis. This mantis is predominantly green and has a less elongated appearance. These are quite a common sight as they are attracted to our windows in the summer, preying on the many other insects attracted to the lights. We have seen as many as three on one evening and they are so regular as to well merit the name of Garden Mantid.
On 20th May 2007, I was examining plants in our shade house, when I saw what looked like a small piece of polystyrene, wedged in the axil of a leaf of one of the pot plants. On close examination I realised that it was some sort of egg case. It consists of about 14 cylindrical eggs, arranged in two rows and with foamy material packed around them. I suspected that they were eggs of a praying mantis, and a bit of searching on the internet seemed to confirm this and strongly suggested that these belong to the Garden Mantid.
The mantid egg case is named an Ootheca and is a cluster of eggs. To photograph the ootheca, I had to replace it in the leaf axil for a reasonably correct photo. I then decided to try and see the young emerge.
Having already dislodged the ootheca from the plant, I decided to glue it to a dry gum leaf (using PVC adhesive) and I placed the leaf in a jar in a position where I would see it every day.
After a month or so, I worried that the atmosphere in the jar was too dry, and I added a little water to the bottom of the jar. This was a mistake. After another week or two, I noticed that a mould was growing over the sides of the ootheca. I quickly got rid of the water and left the lid off for a while so that it could dry out. The mould very quickly disappeared, but I continued to worry that the fungus might have had a bad effect on the eggs.
On 24th August, 3 months after I found the ootheca, I was thrilled to see tiny little mantids in the jar beside the ootheca.
At this stage there were three visible, one of which was still attached to the ootheca and seemed to have its antennae and legs bound to its body. I quickly got my camera and photographed the little mantis. The photo attached, shows two baby mantis.
One baby is fully emerged and was running about. It looks the same shape as the Garden Mantis adult, but in miniature (it was about 11 mm long), except that it has an orange-brown stripe down the middle of the back, which could be its gut showing through its thin skin. The second animal (in the top of the picture, which also shows the ootheca) took only 5 minutes of wriggling to free itself and it was soon running about freely as well.
Once I was happy that I had them recorded on the camera, I released the babies in the shade-house, where I originally found the ootheca, and I also placed the ootheca in the shade house, so that any further babies to emerge would be free in the habitat chosen for them by their mother!